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Pulsar Glitch Activities:The Spin Parameters Approach

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Research in astronomy and Astrophysics 2024年第6期24卷 334-357页

作者： Innocent Okwudili Eya Evaristus Uzochukwu Iyida physics/Electronics Technique—Department of science Laboratory Technology University of NigeriaNsukkaNigeria Department of physics and astronomy University of NigeriaNsukkaNigeria astronomy and Astrophysics Research Lab University of NigeriaNsukkaNigeria

Glitch activity refers to the mean increase in pulsar spin frequency per year due to rotational *** is an important tool for studying super-nuclear matter using neutron star interiors as *** events are typically observed in the spin frequency(ν) and frequency derivative( ν) of *** rate of glitch recurrence decreases as the pulsar ages,and the activity parameter is usually measured by linear regression of cumulative glitches over a given *** method is effective for pulsars with multiple regular glitch ***,due to the scarcity of glitch events and the difficulty of monitoring all known pulsars,only a few have multiple records of glitch *** limits the use of the activity parameter in studying neutron star interiors with multiple *** this study,we examined the relationship between the activity parameters and pulsar spin parameters(spin frequency,frequency derivative,and pulsar characteristic age).We found that a quadratic function provides a better fit for the relationship between activity parameters and spin parameters than the commonly used linear *** this information,we were able to estimate the activity parameters of other pulsars that do not have records of *** analysis shows that the relationship between the estimated activity parameters and pulsar spin parameters is consistent with that of the observed activity parameters in the ensemble of pulsars.

关键词： stars:neutron (stars:)pulsars:general methods:statistical

A Possible γ-Ray Pulsation from PSR J1740-5340B in the Globular Cluster NGC 6397

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Research in astronomy and Astrophysics 2024年第1期24卷 285-291页

作者： Jiao Zheng Pengfei Zhang Li Zhang Department of astronomy School of Physics and AstronomyKey Laboratory of Astroparticle Physics of Yunnan ProvinceYunnan UniversityKunming 650091China

Recently, a new radio millisecond pulsar(MSP) J1740-5340B, hosted in the globular cluster(GC) NGC 6397,was reported with a 5.78 ms spin period in an eclipsing binary system with a 1.97 days orbital period. Based on a modified radio ephemeris updated by tool tempo2, we analyze the ~15 yr γ-ray data obtained from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope and detect PSR J1740-5340B's γ-ray pulsation at a confidence level of ~4σ with a weighted H-test value of ~26. By performing a phase-resolved analysis, the γ-ray luminosity in on-pulse interval of PSR J1740-5340B is L_(γ)~ 3.8 × 10^(33) erg s^(-1) using NGC 6397's distance of 2.48 kpc. And γ-rays from the on-pulse part of PSR J1740-5340B contribute ~90% of the total observed γ-ray emissions from NGC 6397. No significant γ-ray pulsation of another MSP J1740-5340A in the GC is *** that the previous four cases of MSPs in GCs, more data in γ-ray, X-ray, and radio are encouraged to finally confirm the γ-ray emissions from MSP J1740-5340B, especially starving for a precise ephemeris.

关键词： gamma-rays:galaxies (stars:)pulsars:individual(PSR J1740-5340B) (Galaxy:)globular clusters:individual(NGC 6397)

Raman signal enhancement for gas detection using a dual near-concentric cavities group

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Chinese Optics Letters 2024年第5期22卷 47-52页

作者：任一凡杨德旺孙颖欣许家旋刘硕芳陈月娥 Key Laboratory for Microstructural material physics of Hebei Province School of ScienceYanshan UniversityQinhuangdao 066004China College of Ocean science and Engineering Shandong University of Science and TechnologyQingdao 266590China

Effective methods are urgently required to optimize Raman spectroscopy technology to ameliorate its low detection ***,we superposed two near-concentric cavities to develop a dual near-concentric cavities group(DNCCG)to assess its effect on gas Raman signal intensity,signal-to-noise ratio(SNR),and limit of detection(LOD).The results showed that DNCCG generally had higher CO_(2) Raman signal intensity than the sum of two near-concentric ***,the noise intensity of DNCCG was not enhanced by the superposition of near-concentric ***,DNCCG increased the *** LOD for CO_(2) was 24.6 parts per *** could be an effective method to improve the detection capability of trace gases and broaden the dynamic detection range,which might aid the future development of innovative technology for multicomponent gas detection.

关键词： Raman spectroscopy gas detection sensitivity dual near-concentric cavities group

A soft-contact hybrid electromagnetic–triboelectric nanogenerator for self-powered water splitting towards hydrogen production

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Nano Research 2024年第7期17卷 6567-6574页

作者： Fuxue Ma Yingjie Wu Shuge Dai Pei Lin Junlu Sun Lin Dong Key Laboratory of material physics of Ministry of Education and School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450000China

The effective acquisition of hydrogen energy from the ocean offers a promising sustainable solution for increasing global energy ***,a self-powered high-efficient hydrogen generation system is proposed by integrating a triboelectric–electromagnetic hybrid nanogenerator(TEHG),power management circuit(PMC),and an electrolytic *** the wind triggering,as-fabricated TEHG can effectively convert breeze energy into electric energy,which demonstrates a high output current of 20.3 mA at a speed rotation of 700 rpm and the maximal output power of 13.8 mW at a load of 10 MΩ.Remarkably,asdesigned self-powered system can perform a steady and continuous water splitting to produce hydrogen(1.5μL·min^(−1))by adding a matching capacitor between the PMC and electrolytic *** the circuit,the capacitor can not only function as a charge compensation source for water splitting,but also stabilize the working *** other self-powered water splitting systems,the proposed system does not need catalysts or the complex electrical energy storage/release process,thus improving the hydrogen production efficiency and reducing the *** work provides an effective strategy for clean hydrogen energy production and demonstrates the huge potential of the constructed self-powered system toward carbon neutralization.

关键词： wind energy harvester hybrid nanogenerator energy conversion and management hydrogen energy production

Sequestration of helium and xenon via iron-halide compounds in early Earth

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Matter and Radiation at Extremes 2024年第3期9卷 83-88页

作者： Jurong Zhang Hanyu Liu Changfeng Chen Yanming Ma Key Laboratory of material Simulation Methods and Software of Ministry of Education and State Key Laboratory of Superhard materials College of PhysicsJilin UniversityChangchun 130012China School of physics and Electronics Shandong Normal UniversityJinan 250014China International Center of Future science Jilin UniversityChangchun 130012China Department of physics and astronomy University of NevadaLas VegasNevada 89154USA

The terrestrial abundance anomalies of helium and xenon suggest the presence of deep-Earth reservoirs of these elements,which has led to great interest in searching for materials that can host these usually unreactive ***,using an advanced crystal structure search approach in conjunction with first-principles calculations,we show that several Xe/He-bearing iron halides are thermodynamically stable in a broad region of P–T phase space below 60 *** results present a compelling case for sequestration of He and Xe in the early Earth and may suggest their much wider distribution in the present Earth than previously *** findings offer insights into key material-based and physical mechanisms for elucidating major geological phenomena.

关键词： halide searching insight

Metal and ligand modification modulates the electrocatalytic HER,OER,and ORR activity of 2D conductive metal-organic frameworks

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Nano Research 2024年第9期17卷 7984-7990页

作者： Yanan Zhou Li Sheng Lanlan Chen Wenhui Zhao Wenhua Zhang Jinlong Yang School of material science and Chemical Engineering Institute of Mass SpectrometryNingbo UniversityNingbo 315211China Department of Chemical physics University of Science and Technology of ChinaHefei 230026China Department of material science and Engineering University of Science and Technology of ChinaHefei 230026China Department of physics Ningbo UniversityNingbo 315211China Hefei National Laboratory for Physical sciences at the Microscale CAS Key Laboratory of Materials for Energy Conversion and Synergetic Innovation Centre of Quantum Information and Quantum PhysicsUniversity of Science and Technology of ChinaHefei 230026China

It is highly desirable to design efficient and stable hydrogen evolution reaction(HER)and oxygen evolution/reduction reaction(OER/ORR)electrocatalysts for the development of renewable energy ***,density functional theory(DFT)calculations were conducted to systematically investigate a series of TMN_(x)O_(4-x)-HTT(TM=Fe,Co,Ni,Ru,Rh,Pd,Ir and Pt;HTT=hexahydroxy tetraazanaphthotetraphene)analogs of two-dimensional(2D)conductive metal-organic frameworks(MOFs)as potential electrocatalysts for the HER,OER and *** thermodynamic and electrochemical stability simulations suggest that these designed catalysts are ***,CoO_(4)-HTT,RhN_(3)O_(1)-HTT and IrN3O1-HTT are predicted to be the most promising catalysts for the HER,OER and ORR,respectively,surpassing the catalytic activity of corresponding benchmark *** volcano plots were established based on the scaling relationship of adsorption Gibbs free energy of *** results reveal that regulating combinations of metal active centers and local coordination environments could effectively balance the interaction strength between intermediates and catalysts,thus achieving optimal catalytic *** findings not only opt for the promising HER/OER/ORR electrocatalysts but also guide the design of efficient electrocatalysts based on 2D MOFs materials.

关键词： hydrogen evolution reaction(HER) oxygen evolution/reduction reaction(OER/ORR) electrocatalysts design twodimensional(2D)conductive metal-organic frameworks(MOFs) density functional theory(DFT)

Effects of oxygen vacancy on bond ionicity,lattice energy,and microwave dielectric properties of CeO_(2) ceramics with Yb^(3+) substitution

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Journal of Advanced Ceramics 2024年第2期13卷 247-254页

作者： Mingan Shi Shuyang Ma Wangsuo Xia Ying Wang Jinzi Yu Haitao Wu School of materials science and physics China University of Mining and TechnologyXuzhou 221008China School of Environment and material Engineering Yantai UniversityYantai 264005China

Novel Yb_(x)Ce_(1-x)O_(2-0.5x)(x=0-0.8)ceramics,designed by replacing Ce^(4+)with Yb^(3+)ions were prepared by conventional oxide reaction,and the structural stability of the cubic fluorite structure was assessed using lattice energy and ionic properties of Ce/Yb-O *** oxygen vacancy caused by unequal substitution,which played a decisive role in bond ionicity and lattice energy,was analyzed experimentally by XPS and also theoretically by first *** Yb_(x)Ce_(1-x)O_(2-0.5x) ceramics maintain a stable cubic fluorite structure when x≤0.47,corresponding to the minimum lattice energy of 4142 kJ/mol with the lowest ionicity as ƒ_(i)=87.57%.For microwave dielectric properties,when the Yb_(x)Ce_(1-x)O_(2-0.5x)(x=0-0.4)ceramics are pure phase,the porosity-corrected permittivity is dependent on the bond *** Q×ƒ values are related to the lattice energy and grain *** temperature coefficient of resonance frequency has been analyzed using bond *** the Yb_(x)Ce_(1-x)O_(2-0.5x)(x=0.5-0.8)ceramics are multiple phases,the microwave dielectric properties are associated with the phase composition and grain growth.

关键词： structure stability bond ionicity oxygen vacancy electronic localization function(ELF)

Revisit of GeV Gamma-Ray Emission from Orion B with the Fermi Large Area Telescope

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Research in astronomy and Astrophysics 2024年第9期24卷 128-135页

作者： Wei Zeng Xiao-Na Sun Rui-Zhi Yang Jia-Chun He Zhao-Dong Shi Ting-Ting Ge Yun-Feng Liang En-Wei Liang Guangxi Key Laboratory for Relativistic Astrophysics School of Physics Science and TechnologyGuangxi UniversityNanning 530004China Department of astronomy School of Physical SciencesUniversity of Science and Technology of ChinaHefei 230026China CAS Key Labrotory for Research in Galaxies and Cosmology University of Science and Technology of ChinaHefei 230026China School of astronomy and Space science University of Science and Technology of ChinaHefei 230026China School of physics and astronomy Sun Yat-sen UniversityZhuhai 519082China

We revisit the γ-ray emission above 300 Me V towards the massive star-forming region of Orion B by adopting14 yr observations with the Fermi Large Area Telescope and utilizing the updated software *** extended γ-ray emission region around Orion B is resolved into two components(region Ⅰ and region Ⅱ).The γ-ray spectrum of region I agrees with the predicted γ-ray spectrum assuming the cosmic ray(CR)density is the same as that of Alpha Magnetic Spectrometer(AMS-02)measured ***γ-ray emissivity of region II appears to be deficit at low energy band(E<3 GeV).Through modeling we find that CR densities exhibit a significant deficit below 20 Ge V,which may be caused by a slow diffusion inside the dense *** is probably caused by an increased magnetic field whose strength increases with the gas density.

关键词： (ISM:)cosmic rays gamma-rays:ISM (Galaxy:)open clusters and associations:individual(NGC 2023 NGC 2024 NGC 2068 and NGC 2071)

Phonon resonance modulation in weak van der Waals heterostructures:Controlling thermal transport in graphene-silicon nanoparticle systems

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Chinese physics B 2024年第4期33卷 96-102页

作者：李毅刘一浓胡世谦 School of physics and astronomy Yunnan UniversityKunming 650091China

The drive for efficient thermal management has intensified with the miniaturization of electronic *** study explores the modulation of phonon transport within graphene by introducing silicon nanoparticles influenced by van der Waals *** approach involves the application of non-equilibrium molecular dynamics to assess thermal conductivity while varying the interaction strength,leading to a noteworthy reduction in thermal ***,we observe a distinct attenuation in length-dependent behavior within the graphene-nanoparticles *** exploration combines wave packet simulations with phonon transmission calculations,aligning with a comprehensive analysis of the phonon transport regime to unveil the underlying physical mechanisms at ***,we conduct transient molecular dynamics simulations to investigate interfacial thermal conductance between the nanoparticles and the graphene,revealing an enhanced thermal boundary *** research not only contributes to our understanding of phonon transport but also opens a new degree of freedom for utilizing van der Waals nanoparticle-induced resonance,offering promising avenues for the modulation of thermal properties in advanced materials and enhancing their performance in various technological applications.

关键词： thermal conductivity molecular dynamics phonon resonance van der Waals interaction graphene-silicon nanoparticle heterostructure